Some improvements in presentation

slidev/slides.md

@@ -137,6 +137,8 @@ Server owns the secret key and initialization vector (IV) used for encryption
 sequenceDiagram
   Client->>Server: cipher length (4 bytes): 0x00000010
   Client->>Server: ciphertext: 0x00112233445566778899aabbccddeeff
+  Server->>Server: decrypt ciphertext
+  Server->>Server: check padding
   Server->>Client: padding status (1 byte): 0x00 (correct padding)
 ```
 
@@ -153,7 +155,11 @@ Suppose the following setup:
 - Plaintext: $p_1, p_2, p_3, p_4$
 - Ciphertext: $c_1, c_2, c_3, c_4$
 
-We want to decrypt $p_3$
+We will start to decrypt $p_3$.
+
+By definition of CBC, we know that:
+
+$$c_3 = E_k(p_3 \oplus c_2)$$
 
 ::right::
 
@@ -173,7 +179,7 @@ We know that
 
 $$p_i = D_k(c_i) \oplus c_{i-1}$$
 
-Let's generate a random bloc $x$ and concatenate $c_3$ and $x$
+Let's generate some random bloc $x$ and concatenate $x$ and $c_3$.
 
 Using our diagram, we can write the following: